Superheater.



Patented Dec. I6, 1902.

J. P. SNEDIJUN. SUPERHEATEB. (Application filed Mar. 11, 1902.) (No Modql.) 2 Sheets-Sheet l.

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Un ren STATES PATENT FFIGE.

JAMES P. SNEDDON, OF BARBERTON, OHIO, ASSIGNOR TO THE STIRLING OOMPANY, OF JERSEY CITY,

JERSEY.

NEW JERSEY, A CORPORATION OF NEW SUPERHEATER.

SPECIFICATION forming part of Letters Patent No. 716,300, dated December 16, 1902. Application filedMarch 11, 1962. Serial No. 97,733. (No model.)

To all whom it may concern:

Be it known that'I, JAMES P. SNEDDON, a

. resident of Barberton, in the county offiummit and State of Ohio, haveinvented a new and useful Improvement in Superheaters; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to steam-superheaters; and its object is to providea superheater whereby a very high temperature can be maintained without danger of overheating the tubes and whereby a very rapid velocity of the steam through the tubes is secured, thereby securinga very high efficiency of the superheater.

To this end the invention consists in providing a series of horizontal headers, to which the superheater-tubes are connected, and so arranging the connections that the saturated steam will be admitted to. the lower one or ones of said headers andafter being heated in the tubes connected thereto passing to the upper header or headers for a final superheating. By admitting the saturated steam into the lower clusters of tubes a much higher initial temperature can be maintained without danger of burning these tubes.

The invention also comprises a construction of headers and tubes wherebya Very high velocity of the steam through the superheat ers is secured, this construction comprising headers having two compartments and tubes connected thereto comprising inner and outer tubes, the inner ones being connected to one of the header-compartments and the outer ones to the other header-compartment.

In the accompanying drawings, Figure 1 is a vertical section through the superheater. Fig. 2 is a front view of the same; and Fig. 3 is a plan view, partly in section, of one of the headers witha cluster of tubes connected thereto.

The superheater will be located in any suitable heating-chamber 1, which is inclosed by masonry or other walls 2 and being heated from any suitable source of heat. In the drawings I have shown for this purpose a furnace-grate 3 located beneath the superheater, so that the flame .and hot gases will pass up from said furnace through the superheatertubes and'out to the stack through an outlet 4 at the top of the heating-chamber 1. The superheater-tubes are shown as extending horizontally across the heating-chamber l,

and projecting into said chamber alternately from opposite sides thereof are the baffleplates 5, which deflect the flame and hot gases and make them take a circuitous path through the tubes, as will be readily understood. Any other arrangement of furnace and baffle-walls, however, might be employed.

The superheater-tubes are preferably arranged in clusters, as shown, and connected to the horizontal headers 6, which preferably are square in cross-section, as shown, and said headers are arranged in two or more groups, preferably three, and the steam connections are such that the saturated steam will first pass into the lower group of headers and through the tubes connected thereto, thence to the upper group of headers, and finally to the middle group of headers. In the particular superheater shown there are nine headers, arranged in three groups of .three each, the lower group 7 having the steam-inlet 8 connected thereto and said group being connected in turn by the pipe 9 to the upper group of headers 10, and these in turn are connected by the pipe 11 with the middle group of headers 12, to which group the steam-outlet pipe 13 is connected. Suitable controllingvalves will be placed in the various pipes, as desired or necessary. The greatest heat in the heating-chamber is of course at the point nearest the source of heat, which in the particular superheater shown will be at the bottom of the chamber 1, so that the superheater-tubes connected to the lower group of headers will be exposed to the highest heat. By admitting the saturated steam into this group of tubes a much higher initial temperature can be maintained without danger of burning the tubes,

as the steam will tend to some extent to cool these tubes. After passing through these tubes the steam is led through the pipe 9 to the upper group of tubes, where it is further superheated and is then led by the pipe 11 to the middle group of tubes, where it takes its finalsuperheating and is raised to a very high temperature.

In order to secure the best results, it is essential that the steam should pass through the superheating-tubes at a very high velocity, and this is best secured by having a construction of headers and tubes wherein inner and outer tubes are used, and I have shown a construction of this kind which is essentially the well-known construction of the Niclausse steam boiler. This construction is shown in Fig. 3. The headers each have two compartments 14 and 15, separated by a 1ongitudinal diaphragm 16. One of these compartments-as, forinstance,the compartment 14is the receiving-compartment, while the other compartment'as, for instance,the compartment 15-is the outlet-compartment. The superheater-tubes comprise outer tubes 17, which have their rear or outer ends closed, as at 18, and inner circulating-tubes 19, projecting into said outer tubes and having their outer ends open and in proximity to the closed ends of the outer tubes. The outer tubes are connected to the inner wall of the header and communicate with the compartment 15, while the inner tubes 19 are connected to skeleton frames 20, secured in alining openings in the front wall and diaphragm of the header, and

said inner tubes communicate with the compartment 14. The construction of the header having two compartments and the inner and outer tubes connected thereto is substantially the same as that of the well-known Niclausse boiler, and further detailed description thereof is unnecessary. Suffice it to say that the steam, entering said headers passes from the compartment 14 through the skeleton frame 20 into the inner circulating-tubes 19 and through the latter to the rear ends of the outer tubes 17, and thence passes forward through the annular space between the inner and outer tubes to the compartment 24, and thence out through the same. By this arrangement of headers having two compartments and inner and outer tubes com municating,respectively, with said compartments a very high velocity is given to the steam. This is due to the fact that the total volume of steam must pass through the annular space between the inner and outer tubes, and as the area of this annular space is much less than the area of a plain tube a corresponding increase in velocity of the steam is secured. By arranging the headers in a horizontal position and in groups, as shown, the velocity of the steam is further increased and saturated steam is confined to the three lower headers, where the temperature of the surrounding gases is high est, so that a higher initial temperature is maintained than could be done if the headers were arranged vertically and the saturated steam admitted to all at the same time or if the steam were admitted to the upper ones of the horizontal headers. The rapid velocity of the steam through the superheater rolls the steam over and mixes it up rapidly, thus bringing the cooler portions of the steam continuously in contact with the hotter heatingsurface, thus greatly increasing the efficiency of the superheater, as there is a very large heat transfer of thermal units per square foot of heating-surface per each degree difference of temperature, and it has been found that by actual test this transfer of thermal units per square foot of heating-surface per each degree difference in temperature is very much higher than in any other construction of superheater, this being due to the high velocity imparted to the steam by the use of the inner circulating-tubes.

- What I claim as my invention,and desire to secure by Letters Patent, is

1. In a superheater for steam-boilers, the combination with a heating-chamber, a plurality of horizontal headers each comprising two compartments, superheater-tubes connected thereto and projecting into the heating-chamber, each of said tubes comprising an outer tube connected to one of the header compartments and the inner tube connected to the other header-compartment, steam-inlet connections to the lowermost of said header or headers, connections from the same to the upper header or headers, and steam-outlet connections from the last-named headers.

2. In a superheater for steam-boilers, the combination with a heating-chamber, of three groups of horizontal headers, superheatertubes connected thereto and projecting into the heating-chamber,steam-inlet connections to the lower groupof headers, steam-outlet connections from the middle group of headers, and connections between the lower and Ico upper groups and between the upper and middle groups.

3. In a superheater for steam-boilers, the combination with a heating-chamber,of three groups of horizontal headers, each header be- 105 ing provided with two compartments, superheater-tubes connected to said headers and projecting into the heating-chamber, each of said tubes comprising an outer tube con nected to one header-compartment and an in- 1 IO ner tube connected to the other header-compartment,steam-inlet connections to the lower group of headers, steam-outlet connections between the lower and upper groups of headers and between the upper and middle groups 1 15 of headers.

In testimony whereof I, the said JAMES P. SNEDDON, have hereunto set my hand.

' JAS. P. SNEDDON.

Witnesses:

E. E. BAKER, J. CLARENCE FRANK. 

